Yes, I'm aware that the majority of genes are not phenotypically expressed - appearance, or physical manifestation, is such a small percentage of who we are as a species.
I think the purpose was the after mapping (and knowing the function of) the operons, was to find out what would happen if introns were knocked out too. I think the resultant mice was more (way more) than they had ever expected.
As far as organism size vs. genetic information - I find that interesting as well!! I didn't know that about the amoeba.
What I find most interesting is the inability of prokaryotic organisms to process introns. Like when they used E. coli to make human insulin.
My point was that someone must have identified that region as something interesting to knockout beforehand. I am sure it wasnt just some nondescript junk DNA.
Yes, I'm aware that the majority of genes are not phenotypically expressed - appearance, or physical manifestation, is such a small percentage of who we are as a species.
Ahhh...but realize that there was a good reason for knocking out these genes in mice in the first place. These are expressed sequences that show promising results in tissue culture cells, enough to justify making a $100,000 mouse. And in many (if not most) of these cases, there is no effect on viability or even a phenotype in these animals.
I think the purpose was the after mapping (and knowing the function of) the operons, was to find out what would happen if introns were knocked out too. I think the resultant mice was more (way more) than they had ever expected.
I think you have your terminology confused a bit here. The term "operon" refers to clusters of genes in prokaryotes that are all expressed simultaneously (i.e. lac operon). Perhaps you meant exons - the protein coding portion of the gene?
Introns do serve important functions. First of all they seperate exons and allow for alternate splicing and shuffling exons for a given mRNA to potentially generate several different proteins. Also we are finding more and more that introns hold important regulatory sequences which control the rate of gene expression.
Introns are a very big problem for evolution for a couple of reasons:
1. a whole system is required to splice the DNA properly when there are introns present so that the correct protein be produced. Therefore the jump from prokaryotes without them and eukaryotes with them requires the development of a complete system individualized for the expression of each gene that has an intron. An impossible task by random chance.
2. the system for splicing needs to know exactly what to keep and what to leave out. Even in similar species the introns are different in length and in number. This makes again for the impossibility of such changes having occurred by mere chance.